A cobpobation



July 5, 1921.

F. H. OBERSCHMIDT CONTROLLER FOR POWER OPERATED MACHINES Filed Nov. 25.1921 I INVENTOR. ("a-MM EMMWM ATTORNEY Patented July 5, 1927.

' UNITED STATES PATENT OFFICE.-

rnnnamcx 'r'r. onanscmrm'r, or cnnvnnann, onro', ASSIGNOR 'ro 'rmc'cumminme. 00., or umwauxna, WIBOONSIN,- A coaroaarron or wrsoonsm.

(DNTBOILEB I03 POWEB-OPEBA TED MACHINES.

- Application aled November 85, 1921. Serial No. 517,776.

This invention relates to controllers for and a co-operating platen 2reciprocable by power operated machines and moreparticularl to safetycontrollers for machine tools. ertain types of machines are driven 8through the medium of a clutch controlled by the operator and aresometimes provided with safety controllers including an electromagneticlatching device for lockmg the clutch in its'released position and apair of manually controlled switches for controlling the energizingcircuit of said device. Such switches are connected in series in theenergizing circuit of said device and are located out of proximity tothe movln parts of the machine whereby it is im ossi le for v theoperator to start the mac me while either of his hands are in adangerous position.

However, such safety controllers do revent the operator from removm hlsands from the control switches and eeping the machine in continuousoperat1on, and the present invention has among its ob ects to provide asafety controller which is a aptnot " ed upon release of either controlswitch toefiect automatic sto ping of the machine after a given cycle 0operation thereof.

Another object is to provide a safety controller of the character abovestated including-an electro-magnetic clutch which is manually controlledto efiect startmg ofthe machine and is automatically controlled-toeffect stopping of the machine after a given cycle of operation thereof.

Various objects and advantages of the mvention will hereinafter appear.

The accompanying drawing illustrates an embodiment of the inventionwhich will now be described, it being understood that the embodimentillustrated is susceptible of modification and can also be applied toother types of machines than that illustrated m t e drawing.

In the drawing Figure 1 is-a schematic view'of a controller embodyingthe invention, the same bein shown in connection with a conventiona ty eof toggle press; Fig. 2 is a front elevational view of a mechanicalembodiment of the toggle press with certain of the control parts in Fig.1 mounted thereon.

Referring to Fig. 1 the toggle press Illustrated therein includes astationary head 1 a cam 3 through the medium of a to lo 4. Cam 3 isfixed to a shaft 5 whichis1iven from a shaft 6 through the medium of aclutch 7. Shaft 6 has the usual cone pulley 8 fixed thereto for drivingthe same and 18 also provided with the usual fly wheel 9,

Field member 7" of clutch 7 is keyed to shaft 6 while the armaturemember=7 of said clutch is rotatably mounted on said shaft and has apinion 10 fixed thereto. Pinion 10 meshes with a gear 11 fixed to acountershaft 12 and said countershaft has a pinion 13 fixed theretowhich meshes with an internal gear 14 fixed to shaft 5. i

The controlmeans for the aforedescribed toggle press includes a snapswitch 17, a palr of push button switches 18 and 19 and a pair ofdouble-pole switches 20 and 21. As shown in Fig. 2 push button switches18 and 19 are mounted in front of the press andupon opposite sidesthereof and as hereinafter setforth the same when simultaneouslydepressed serve to establish an energizing clrcuit for clutch 7.Switches 20 and 21 are provided with cam actuatin members 22 and 23respectively and as ereinafter set forth, each of said switches is adated to establish a maintaining circuit for c utch 7 independently ofpush buttons 18 and 19. Cams 22 and 23 are mounted for angular adustmentupon a shaft 24 said shaft bei driven at a speed correspondingto the speofshaft 5 through the medium of a driving connection 25. i

The function and operation'of the aforedescribed controller togetherwith the circuit connections, thereof will now be more fully described.Assuming that switch 17 is closed and that it is desired to start thepress, push buttons 18 and 19 are simultaneously de ressed to establishan energizing circuit or clutch 7. Such ener 'zlng circuit extends fromline L through swltches 17 and 18 by conductors 25 and 26 to and throu hthe winding of clutch 7 by conductors 2 and 28 to and through switch 19to line L. Upon engagement of clutch 7 cam 3 is driven in a clockwisedirection and durin each revolution of said cam, platen 2 is raised andlowered and each of the cams 22 and 23 makes one complete revolution.Cam 22 isarranged so that during upward movement of platen 2 the samecloses switch 20 while cam 23 is arranged to close switch 21 followingclosure of switch 20. Upon 010: sure of switch 21.cam 22 permits openingof switch 20 and upon completion of the cycle of operation of platen 2cam 23 permlts opening of switch 21. Either of the switches 20 and 21when closed establishes an energizing circuit for clutch 7 extendingfrom line L through the left hand pole of said switches by conductors 30and 26 to and through the winding of clutch 7 by conductors 27 and 31through the right hand pole of said switches to line L. 'By enablingrotary angular adjustment of one or both of earns 22 and 23 with respectto shaft 2 1, in the manner aforeindicated, the duration of automaticcontrol of the clutch energization within each cycle of operation of thedevice may be increased or decreased as desired.

From the foregoing it is apparent that after a given upward movement ofplaten 2 the operator is free to remove his hands from push buttons 18and 1.9 to prepare the maternal for the next operation of the press. Assoon as the press starts on its downward stroke the operator removes thefinished part and inserts raw material for the next operation. If theoperator finishes this work before the platen is in position to.

again begin the upward movement he simply holds push buttons 18 and 19depressed until switch 20 establishes-the maintaining circuit for clutch7. Should the operator for some reason fail to complete the work u oncompletion of the downward stroke of p aten 2, switch 21 interrupts themaintaining circuit of clutch 7 to effect automatic stopping of thepress.

What I claim is new and desire to secure by Letters Patent is:

1. In a safety device, the combination with a press having areciprocating. member, an electromagnetic clutch for transmitting powerthereto, right and left hand switches on said press biased to openposition and adapted while simultaneously held closed to maintain anenergizing circuit for said .clutch, a plurality of switches actuated bysaid press and adapted to close successively and open successively afterclosure of said first-mentioned switches to maintain an energizingcircuit for said clutch throughout the remaining part of a cycle ofoperation of said press, and means for varying the time of closure ofcertain of said lastmentioned switches with respect to said cycle ofoperation.

2. In a safety device, the combination with a driven machine, of anelectromagnetic clutch for transmitting power thereto, manuallycontrolled switches adapted while closed simultaneously to establish andmaintam an energizing circuit for said clutch, and adjustable meansassociated with said mamas machine for establishing a maintainingcircuit for said clutch following initiation of the cycle of operationof said machine, said ineans'being adapted to interrupt saidmaintairiing circuit only upon completion of said 0 c e.

3. The combination with a machine of an electro-magnetic clutch fortransmitting power thereto, safety control means for said clutchincluding a plurality of manually controlled switches adapted whileclosed simultaneously to establish and maintain an energizing circuitfor said clutch, and a plurality of switches operated by said machinefor establishing a maintaining circuit for said clutch during a givenpart of the cycle of operation of said machine, and means for varyingthe time of establishment of said maintaining circuit with respect tosaid cycle of operation.

4. The combination with a driven machine, of an electromagnetic. clutchfor transmitting power thereto, safety control means for said machineincluding a plurality of manually controlled switches biased to openposition and adapted while closed simultaneously toestablish andmaintain anenergizin circuit for said clutch, means actuated by saidmachine for establishing an energizing circuit for said clutchindependently of said switches, said means being adapted to establishsaid independent circuit following initiation of the cycle of operationof said machine and to interrupt the same upon completion of said cycle,and means for varying the time of establishment of said independentenergizing circuit with respect to said cycle of operation.

5. The combination with a machine, of an electromagnetic clutch fortransmitting power thereto and safety control means for said machineincluding a plurality of spaced manually operated switches biased toopen position adapted while held closed to maintain an energizingcircuit for said clutch, a pair of switches actuated by said machine,said latter switches being adapted to establish a maintaining circuitfor said clutch independently of said former switches and being adaptedto close successively and open successively, and means for varying thetime of closure of said latter switches with respect to each other. 4

6. The combination with a driven machine, of an electro-magnetic clutchfor transmitting power thereto, a plurality of normally open pushbuttons adapted while simultaneously depressed to maintain an energizingcircuit for said clutch, a plurality of switches actuated by saidmachine, said switches being adapted to close successively and opensuccessively, whereby one of the same is adapted to establish amaintaining circuit for said clutch following initiation of the cycle ofoperation of said machine and nausea the other is adapted to interruptsaid maintaining circuit upon completion of the cycle of operation ofsaid mac me.

nection of said elements, a circuit for said member, a plurality ofrelatively widely spaced manually controlled switches adapted duringsimultaneous closure thereof to effect uninterrupted energization ofsaid circuit, and means contro led by said driven element toautomatically maintain said electromagnetic member energized fora givenperiod to thereby permit tempora release of "said manuall controlledswitc es during each cycle 0 operation.

8. In a safety device for presses and the like having a predeterminedcycle of operation, the combination with power operated driving anddriven elements, an electromagnetic clutch for connectin anddisconnecting said elements, clutc controllin means comprising a circuitand ri ht-han I and left-hand switches adapted while jointly closed toefiect and maintain energization of said circuit, and an adjustablelimit switch controlled .by said driven element and adapted to providean alternative energizing circuit for said clutch only during apredetermined portion of said cycle of operation to thereby permittemporary release of said right-hand and left-hand switches.

9. In a safety device for presses and the like having a predeterminedcycle of operation, the combination with power operated driving anddriven elements, an electromagnetic clutch for connecting anddisconnecting saidelements, clutch controlling means com rising acircuit and right-hand and leftand switches adapted while jointly closedto initiate and maintain said cycle of operation, a. plurality ofsequentially closed and sequentially opened limit switches controlled bysaid driven element and adapted to provide an energizing circuit forsaid clutch independently of said first mentioned switches during apredetermined portion of said cycle of operation, and means forincreasing or decreasing the portion of said cycle of operationsub'ected to automatic 1 control by said limit swltches.

In witness whereof, I have hereunto sub- 55 scribed my name.

' FREDERICK H. OBERSGHMIDT.

